Test plot study of a tailings stack final cover prototype

Waste storage facilities must be protected against weathering once mining operations come to end, in order to ensure structural integrity and to avoid environmental pollution. Cover systems consisting on earthen materials layers that are placed over the wastes are a widely spread solution to fulfil such requirement. This paper presents an experimental study of a cover system intended to protect a waste storage facility study case located in the arid eastern foothills of the Central Andes range, Argentina. At the study case, filtered tailings and waste rock are stored conjunctly. Both materials are stacked as alternating layers, roughly one-meter thickness each. The cover prototype is comprised of the stack topmost tailings layer, which is expected to act as the store-and-release element of a WB cover. The prototype design also includes a waste rock layer placed on top of the tailings, to avoid wind and runoff erosion. A total of 6 study plots have been setup, each equipped with water content and matric suction sensors. The plots location was decided to tackle cover response under sloping and horizontal ground conditions. The performance of three different waste rock layer thicknesses are being studied under both placement inclinations. Available data shows that the prototype comprising a 10cm thick waste rock layer has served satisfactorily to avoid deep percolation and tailings erosion.